Dual Batteries

[chautauquasun]

I am looking at running two batteries this year using the Surepower system. I have a question....If I am running the stereo and it drains the reserve/stereo battery with it then switch over to the starting battery and drain that one too? I think you answered my question above but want to make sure.

Also, do I need to upgrade the Alt? This has more to do with the time it takes to charge everything back up. Correct?

[87SunSportMikeyD]

The SurePower is both a battery seperator and combiner. The system keeps the batteries seperate for everything except starting-assist IF the main battery is low. Your stereo would be hooked up to your 2nd battery. So if you drain your stereo, it is dead (hypothetically). Then you would start your boat and the SurePower would link batteries and begin charging both. Since the batteries are now linked you would get stereo power back as long as you were driving and charging.

You do not NEED to upgrade the alt but I would highly recommend it because it's very easy and cheap. You likely have a 35amp alt now, my new one is 105amp. Also it has better internal circuitry to be sure the alt is providing a steady current that doesn't jump around or surge so much. (Again I am not a mechanic so I am explaining to the best of my ability. No flames, but positively worded corrections are WECOME)

http://www.db-starter-alternator.com...Wire%20ADR0334

Here is the one I got but you may want to look at your current setup and call this company. I think it was Ron at DB. He was SO smart! The alt is made in USA with 1yr warranty for $70.

[jonyb]

The SurePower is both a battery seperator and combiner. The system keeps the batteries seperate for everything except starting-assist IF the main battery is low. Your stereo would be hooked up to your 2nd battery. So if you drain your stereo, it is dead (hypothetically). Then you would start your boat and the SurePower would link batteries and begin charging both. Since the batteries are now linked you would get stereo power back as long as you were driving and charging.

So it links the dead battery and the charged battery together, thus dragging down the charged battery. Would that not be correct?

What I've done in the past with situations like that, is to use a 200A Relay/Isolator. If does basically the same thing, but instead of using the ignition key to trigger it to connect, I wire in a manual toggle switch. That way the boat owner can leave it separated until the boat is started and idling, then flip the switch and connect the batteries. That's only if they don't have an onboard charger because it's pointless at the end of the day to connect the stereo battery to the alternator for a 10 minute ride back to the ramp.

[87SunSportMikeyD]

The SurePower would not link the dead stereo batt with the full main batt untill after you were starting and driving about 1000rpm. The SurePower can use the 2nd battery as starting assist if the MAIN battery is low but otherwise it will not use the 2nd battery at all except to charge it.

Personally I don't have that kind of drain, I can run my stereo for days (a long time anyways) off of my deep cycle battery without draining it all the way and it's not that expensive of a batt.

Using the SurePower I personally never had to charge a battery last year using anything but the alternator. But I wakeboard all day too, I dont' sit in the cove and bump for more than a couple hours.

[chautauquasun]

Thanks Mikey...I order the Surepower 1314 and i have a several old deep cycle batteries that are still good. I am going to wire the stereo directly to the deep cycle battery and use the Surepower to connect my deep cycle and high amp starting battery together. Looks to be a very clean and simple way of doing this. I like that there are no switches to worry about and the Surepower system makes all of those decisions...it can then just worry about listening to tunes and not worry about not starting when I am ready to leave.

DB electrical is a great vendor. I bought a fantastic starter from them last year very cheap and with a great warranty. I cant say enough good things about them or the starter.

thanks for all of your help on this. I now know exactly how I am going to wire everything up.

thanks

Dan

[jonyb]

The SurePower would not link the dead stereo batt with the full main batt untill after you were starting and driving about 1000rpm. The SurePower can use the 2nd battery as starting assist if the MAIN battery is low but otherwise it will not use the 2nd battery at all except to charge it.

I was unsure of that......

[87SunSportMikeyD]

Chaut great to hear! Yup it is super simple and no switches. I agree about the DB elec too they really took good care of me.

I have used it for a year and am very happy. I really dont even notice it's there. The new alt lends a lot of piece of mind too. I should really get brettyates/polarbill in here to talk about it.

[Okie Boarder]

I'm starting to figure out which way I'm going to take this. Does anyone have pics they can post of their set up? I'd love to see the connection configuration on the sure power as well as any others.

[smoothfootn]

Have a perko in my dads tige. It works great. We just select one battery when stopped listening to the redio. When you're ready to go, if it doesn't start on that battery, you still have a completely fresh battery 2. Rest of the time we leave the switch in both so it charges both. REMEMBER that if you let one battery run down and the other is good AND the switch is on both, you have the average of the two voltages. ( 9 + 13 ) / 2 = 11 which is not enough! Be aware if the other system uses both batteries to start after one gets low.

[rludtke]

On my previous boat, I had a system setup using an isolator, I chose the "Hellroaring" one.

It is SUPPOSED to isolate your batteries electronically - so they can both be
charged, but used independently. The one I used has a switch I installed under the dashboard that would allow me to "combine" the batteries if I needed it -

Hi Okie,
I don't have dual batteries in my boat, but if I was going to, I would be set it up like my motorhome, which is just like TG's description. The electronic isolator will keep both batteries charged by the alternator, and yet maintain separation of the "house" and "chassi" systems. My motor home also feature a big, heavy shunting switch on the dashboard that will connect the systems togather to allow you the option of using the "house" battery to start the engine if the "chassi" battery goes dead.

There are a lot of surplus motor home parts on the internet (and Ebay stores) which could be useful source for economical parts.